Pneumatic tool.



E. M. TO

PNEUMATIC T APPLIOATION FILED MAR. 19, 1913.

1,086,955. Patented Feb. 10, 1914,

I 2 SHEETS-SHEET 2.

' TED STATES PATENT OFFICE.

EDWARD M. TOBIN, OF BARRE, VERMONT, A$SIGNOR TO TROW & HOLDEN ('30., OF

. BARRE, VERMONT.

PNEUMATIC TOOL.

To all whom it may concern:

Be it known that I, EDWARD M. TOBIN, a citizen of the United States, and a resident of Barre, in the county of Washington and State of Vermont, have invented a new and Improved Pneumatic Tool, of which the following is a full, clear, and exact description.

This invention relates to improvements in pneumatic tools, and particularly to what are known as pneumatic hammers, and has for an object to provide an improved structure wherein the various moving parts are reduced to a minimum, and the action is without unnecessary vibration or ars.

A further object of the invention is to provide a pneumatic tool with an improved arrangement of head or box and passageways therein, associated with an improved single movable valve member, whereby the air actuating the hammer is properly admitted and exhausted without causing any substantial back pressure.

A still further object of the invention is to provide an improved structure wherein the arrangement of passageways and the various moving parts are adapted to cause the air to properly act upon the hammer in order that the hammer may utilize to substantially the fullest extent the air, and thereby produce a maximum effort for any given quantity of air used..

In carrying out the objects of the invention, a body or shell is provided designed to receive a reciprocating hammer formed with a reduced portion near one end for admitting the passage of air from certain passage ways in the shell or body to other passageways, whereby pressure may be communicated to the bottom of the hammer for raising the same after each stroke. Associated with the outer shell or body is a disk or cap for properly controlling the intake and exhaust from above the hammer, and also for properly guiding air under pressure to the valve arranged thereabove. This valve arranged above the cap is designed to control the air admitted to the shell or body above the hammer, and to properly shut off the air during the return stroke of the hammer. A suitable box or valve housing is provided, arranged with certain apertures and passageways, shut off and again turned on in proper sequence by the valve so as to allow a proper intake and exhaust of the air re- Specification of Letters Patent.

Application filed March 19, 1913.

Patented Feb. 10,1914.

Serial No. 755,373.

gardless of the speed of reciprocation of the hammer. A suitable hood is arranged to be fitted over the valve housing or box and preferably part of the outer shell or body so as to properly direct the air to the valve box or housing and to provide means by which the tool may be manipulated or moved from one place to the other. A practical embodiment of the invention s represented in the accompanying drawlngs forming a part of this specification, in which similar characters of reference indicate corresponding parts in all the views.

Figure 1 is a longitudinal vertical section through a pneumatic tool embodying the invention; Fig, 2 is a view similar to Fig. 1, except that the various parts have been shown in an opposite position; Fig. 3 is a fragmentary longitudinal vertical section through the upper part of the structure shown in Fig. l, the same being shown in perspective and on an enlarged scale with the valve removed; Fig. 4 is a section through Fig. 3 on the line 4 4c; and Fig. 5 is a detail perspective viewof a cap or disk embodying certain features of the invention.

Referring to the accompanying drawings by numerals, 1 indicates the body or shell of the tool, and 2 a hood surrounding the upper part of the body 1 and also the cap or disk 3, as well as the valve casing 4. The upper part of hood 2 merges into a handle 5 designed to be used for shifting the position of the tool from one place to another. The handle 5 is provided with an air passageway 6 connected with any de sired source of air supply, and which is adapted to direct air into an air feed chamber 7 in the top of hood 2, where the air is designed to maintain a continuous pressure in passageways 9 andlO of the valve housing 4. The passageway 9 is designed to register with passageway 11 in the cap or disk 3, which in turn is continuously in register with passageway 12 in the, shell 1. Passageway 12 is'provided with an exhaust or outlet 13, whereby the pressure maintained in passageways 9, 11 and 12 will exreduced portion 14, a head 16, a body 17, a lower reduced portion 18, and a striking portion or end 19. The striking portion or end 19 is adapted to snugly fit the bore 20, which is provided with an exhaust port 21, while the body 17 is adapted to snugly fit the bore 22, thesnug fitting of the parts of the hammer being only sufiicient for preventing the passage of air, but the fit is not sufliciently tight for preventing a proper free reciprocation of the hammer. When the hammer is in the position shown in Fig. 1, the air pressure will pass into the space around the reduced portion 14, and from thence pass through opening 23 into passageway 24. The passageway 24 extends from the casing or shell where it registers with opening 25 in disk3, to the opening or port 26 arranged immediately above the bore 20. An intermediate exhaust port 27 is arranged between ports 23 and 26 so as to allow a quick exhausting of the combined air in passageway 24. After the air. has passed from around the reduced portion 14 into the passageway 24, the same passes through outlet 26 and also the passageway 25 in disk3. l/Vhen passing through the outlet 25 in disk 3, the air is guided through a passageway 28 in disk 3 to the bore 29 in the valve housing 4. In order to cause a better distribution of the air in bore 29 beneath the valve 30 a hollowed out portion 31 is provided, in free communication with passageway 28. Pressure entering into bore 29 rom passageway 28 will cause valve 30 to be moved toward the end of housing 4, opposite disk 3, and thereby close the passageways 10. This is possible as the area at the bottom of valve 30 is greater than the area of the beveled surface 32 of the upper part of valve 30. In this way, assoon as air is permitted to pass into passageway 24, valve 30 is actuated for shutting off any further supply of air to bore 22 above the hammer 15, and at the same time air under pressure is admitted to the bottom part of bore 22 around the re duced portion 18 of the hammer and thereby causes the hammer to be moved up, or rather toward disk 3 and away from the too-l 33. As soon as the lower end of the portion 19 of hammer 15 is raised above the port or opening 26, the air begins to exhaust into port 20 and from thence out through exhaust port 21. Beforethis exhaust takes place, the body portion 17 is covering port or opening 13 and therefore no fresh supply of air is provided. The action of the air in forcing the hammer 15 toward disk or cap 3, is so strong and quick that the hammer will move to the position almost against disk 3, as shown in Fig. 2, but the momentum thereof can be checked by the inrushing air through the passageways 34 in the cap or disk 3.

4 In connection with the cap or disk 3, it will be noted that the same is provided with a number of passageways 34 arranged at an angle so that the upper ends thereof will register with passageways 35, and the lower ends will open into bore 22. One or more dowel pins 36 are provided in the disk 3 and are arranged to be projected therefrom so as to engage a suitable aperture in the shell or casing 1, and also in the housing 4, so as to properly hold the various passageways in aline'ment.- Preferably two of these dowel pins are used as the same are usually sufliciently strong for properly holding these parts together, and also for properly preventing any twisting or turning action.

The valve casing or housing 4 is arranged immediately above disk 3 and is formed with bore 29, which at the upper end merges into a reduced bore 37 for accommodating the reduced guiding extension 38 (Fig. 1) of valve 30. The extension 38 and the main body of the valve 30 are connected by the beveled surface 32, which when the valve is closed is arranged oppositethe annular groove 39, and when open is arranged opp-osite groove 40. As clearly shown in Fig. 3, the passageways 10 merge into or open into groove 39 so that the air may freely enter groove 39 and from thence pass through part of bore 29 into groove 40 when the valve 30 is in the open position, as shown in Fig. 2. From the groove 40 the air passes through passageways 35 into passageways 34, and from thence into bore 22 above the hammer 15 for causing the same to move downwardly or to strike. After the hammer 15 has been moved for striking and the same is being retracted or moved back to its original position, the air in the bottom of valve 30 will cause the same to move upwardly to the position shown in Fig. 1 for preventing air from passing from groove 39 to groove 40, and at the same time for causing the notched out portions 41 in the valve 30 to provide paths or passageways for the exhaust air from the upper part of bore 22, whereby said exhaust air may pass out passageways 34, 35, annular groove 40, and from thence through the notches 41 and into the radiating exhaust passageways 42. The exhaust passageways 42 open into an exhaust chamber 43, which is in fact an annular groove in the hood 2. It will be evident that the hood 2 may be provided with any desired number of exhaust ports 44 for allowing the proper escape of the air.

Having thus described my invention I claim as new and desire to secure by Letters Patent:

1. In a pneumatic tool, a hammer, a casing for said hammer having an axial opening, a valve housing formed with an axial opening facing the opening in said casing, an air directing disk arranged between said valve housing and said casing, and means mounted on said valve housing and having an annular flange inclosing said casing, said means directing air to said Valve housing, said valve housing and said inclosing means having exhaust passageways, and a reciprocating valve within the axial opening of said housing, said valve having both ends closed and a plurality of spaced notches adapted to lie in the same transverse plane with the above-mentioned exhaust passageways and permit the escape of exhaust from the interior of one end of the valve housing to the atmosphere when the valve is in one position and lie in a different plane and prevent the escape of air when the valve is in the opposite position.

2. In a pneumatic tool of the class described, a casing, a hammer arranged in said casing, a valve structure for supplying air to said casing and directing air therefrom whereby said hammer is adapted to reciprocate, said valve structure comprising a housing formed with a bore, a pair of spaced annular grooves near the upper part of said bore, a passageway leading from the upper end of the casing to one of said annular grooves, air passageways leading from the other of said annular grooves to a point ontering into said casing, and a plurality of exhaust passageways and a reciprocating valve arranged in said bore, said reciproeating valve having notched out portions on the face thereof, and a pair of annular bearing portions whereby when said valve is n one position said second mentioned annular groove may exhaust into the notches in the valve and from thence into the exhaust passageways in said housing and when the valve is in an opposite position, said first mentioned groove is in communication with said second mentioned groove and air under pressure will be forced into said casing above said hammer.

3. In a pneumatic tool, a hammer. a casing for said hammer having an axial open ing, a valve housing connected with one end of. said casing, said valve housing being formed with an axial opening facing the opening in said casing, said valve hous ing being formed with a plurality of radial exhaust openings all arranged in the same plane, a pair of spaced annular grooves arranged above said exhaust opening and a passageway extending from the exterior of said housing to one of said annular grooves, a reciprocating valve member arranged in said valve housing, said valve member being formed with a pair of spaced annular bearing members and with spaced notches between said bearing members, whereby when said valve member is in one of its extreme positions one of said annular grooves will be in communication with said exhaust openings, and when in its other extreme position said annular grooves will be in communication with each other, the valve housing being formed with a passageway extending from said casing to the annular grooves which at times exhaust into said exhaust passageways, whereby when said valve member is in one of its extreme positions the air in the casing may exhaust and when in the opposite extreme position air under pressure may pass from one of said annular grooves to the other and from thence through the passageway connected with last mentioned annular grooves to the interior of said casing.

4. In a pneumatic tool, a hammer, a casing for said hammer, a valve mechanism for controlling the inlet and exhaust from said casing, said valve mechanism comprising a casing formed with a longitudinal bore extending from one end of the casing to near the other end, whereby one end of the easing is closed, an exhaust passageway radiating from said bore, a pair of annular grooves arranged between said exhaust passageway and the closed end of the casing, said annular grooves being spaced apart and one of the same in communication with the top of the casing while the other is in communication with the interior of said casing, a reciprocating valve member arranged in the bore in said casing, said valve member being formed with a pair of annular bearing portions and an end portion adapted to contact with the closed end of the said valve housing when the air under pressure is shut off, said valve member being formed with spaced notches arranged between said annular bearing portions, whereby when said valve member is against the closed end of said casing one of said annular grooves will be in communi cation with said exhaust port, and when said valve member is in the opposite position said annular grooves will be in commu nication with each other, thereby permitting air under pressure to pass into said casing.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

EDIVARD M. TOBIN.

Witnesses JAMES MACKAY, MARY E. SEx'roN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner 0! Patents, Washington, I). G. 

